Modulations in line shapes of magnetoconductance curves for diodes of pentacene:fullerene charge transfer complexes

This work investigates that the applied electric field modulates the line shapes of magnetoconductance (MC) responses in pentacene:fullerene diodes under illumination. We attribute the line shape of MC curves herein is correlated with the strength of the exchange interaction in pentacene:fullerene charge transfer (CT) complex states. Applying the reversed bias increases the built-in electric field (E_built-in) of the diodes to offset the exchange interaction of CT complex states and narrows the line shapes of MC responses. The saturation field of MC curves in the pentacene:fullerene bulk heterojunction device is 752 Oe when the device is biased at 0.4 V and decreases to 212 Oe at a reversed bias of -1.0 V. The line shape of MC curves for the diode made of pristine pentacene or fullerene as the active layer does not change with the applied bias voltage. Our results indicate the correlations of MC responses with the exchange interaction of CT complexes as modulated by the applied electric field.